Effects of combining Renlon with Renbarb1 and Renbarb2 on resistance of cotton (Gossypium hirsutum L.) to reniform nematode (Rotylenchulus reniformis Linford and Oliveira)

Authors: GAUDIN, AMANDA - Mississippi State University; WALLACE, TED - Mississippi State University; Scheffler, Jodi; Stetina, Salliana - Sally; Wubben, Martin

Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2020
Publication Date: 4/6/2020
Citation: Gaudin, A.G., Wallace, T.P., Scheffler, J.A., Stetina, S.R., Wubben, M. 2020. Effects of combining Renlon with Renbarb1 and Renbarb2 on resistance of cotton (Gossypium hirsutum L.) to reniform nematode (Rotylenchulus reniformis Linford and Oliveira). Euphytica. 216:67. https://doi.org/10.1007/s10681-020-02580-3.
DOI: https://doi.org/10.1007/s10681-020-02580-3

Interpretive Summary: Reniform nematodes are parasitic worms that feed on plant roots. The plants are not killed, but are less vigorous and not as productive, often causing the cotton farmer to lose money. Several different forms of natural resistance to reniform nematodes have been identified in wild cotton and transferred into cultivated cotton. LONREN, the best source of resistance, has been reported to exhibit stunting when exposed to very high levels of nematodes, but the other source, BARBREN-713, is not stunted. Often when two different sources of resistance are combined into one cotton line, the level of resistance can be improved and make the resistance more difficult for the nematodes to overcome. Plants with different combinations of the known resistance genes were developed and evaluated to see if they could improve cotton’s productivity in the presence of the nematodes. The results indicated that the plants with a combination of both the LONREN and the BARBREN- 713 resistance traits maintained a high level of resistance, did not exhibit stunting and showed improved growth compared to plants with only one of the sources of resistance or plants with no resistance genes. Combining both sources of resistance into cotton cultivars will help the farmer grow healthy and more productive cotton in fields that are infested with reniform nematodes.

Technical Abstract: The Upland cotton (Gossypium hirsutum L.) germplasm lines BARBREN-713 and LONREN have resistance to reniform nematode (Rotylenchulus reniformis Linford and Oliveria). The presence of the resistance trait can be determined using quantitative trait loci (QTL) designated Renbarb1and Renbarb2 in BARBREN-713 and Renlon in LONREN. Stunting has been observed in the LONREN source of resistance when subjected to heavy nematode pressure but not for BARBREN-713. To investigate the potential to reduce stunting in the LONREN source of resistance, cotton lines were developed with different combinations of reniform nematode resistance loci from LONREN and BARBREN-713. Marker assisted selection was conducted to identify the following QTL combinations 1) Renbarb1 + Renbarb2, 2) Renbarb1 + Renbarb2 + Renlon, 3) Renbarb2 + Renlon,4) Renbarb1+Renlon, 5) Renbarb1 alone, 6) Renbarb2 alone, 7) Renlon alone and 8) a Null susceptible genotype. QTL combinations were inoculated with 0, 2300, or 5000 reniform nematodes per 120 cm3 soil in growth chamber tests. Plants were harvested at 60 days after inoculation, plant growth measurements made and the nematode reproduction factor calculated. In this study, the Renbarb1 genotype was scored as susceptible to reniform nematode. Combining the Renlon with Renbarb2 did not improve resistance to reniform nematode, however, the Renbarb2/Renlon combination had improved growth compared to LONREN-1, BARBREN-713, and the susceptible.